Free Spike Antigen ID’d in Post-SARS-CoV-2 mRNA Vaccine Myocarditis

MONDAY, Jan. 9, 2023 (HealthDay News) -- Individuals who develop myocarditis following a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine have no difference in vaccine-induced immune responses compared with asymptomatic vaccinated controls, although free spike antigen is detected in those who develop vaccine-induced myocarditis, according to a study published online Jan. 4 in Circulation.

Lael M. Yonker, M.D., from Massachusetts General Hospital in Boston, and colleagues prospectively collected blood from 16 patients who were hospitalized for myocarditis after SARS-CoV-2 mRNA vaccination. Extensive antibody profiling was performed and results were compared to those from 45 healthy, asymptomatic, age-matched vaccinated controls.

The researchers found that extensive antibody profiling and T-cell responses were essentially indistinguishable for individuals who developed postvaccine myocarditis and those of vaccinated controls, despite a modest increase in cytokine production. Individuals with postvaccine myocarditis had markedly elevated levels of full-length spike protein, unbound by antibodies, in their plasma, while no free spike was detected in asymptomatic vaccinated controls.

"Although the implications of this finding must be better understood, these results do not alter the risk-benefit ratio favoring vaccination against COVID-19 to prevent severe clinical outcomes," the authors write.

Several authors disclosed financial ties to the biopharmaceutical industry.

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